I just might have the solution for you.
I was facing the exact same issue with Firefox where I could only scroll with two-fingers and single finger selected text.
After a lot of searching I found this Gentoo Wacom page mentioning that the Wacom driver has gesture emulation that causes a problem with Firefox and my Thinkpad X1 Yoga has a Wacom touchscreen.
The fix is to turn off the Wacom gesture setting by creating the following file:
With this configuration:
Identifier "Wacom class"
Option "Gesture" "off"
Resart and enjoy :)